Dockerfile fixes

[maxjacobson]

While pursuing an unrelated bug, I noticed the engine wasn't building.

[dblandin]

You can use a pattern for these two files to avoid the extra layer. Also, since the WORKDIR is already set to /usr/src/app above, you can use ./ for the second argument:

COPY composer.* ./

[maxjacobson]

nice. I see this works, but tbh I don't totally understand it. the COPY directive knows to copy files relative to the Dockerfile into the workdir? cp composer.* ./ wouldn't do anything, but I shouldn't think of COPY and cp as conceptually the same thing, huh?

[dblandin]

Right. COPY in a Dockerfile does not have the same interface or behavior as cp.

Here's a snippet from the docs:

COPY <src>... <dest>

Multiple resources may be specified but they must be relative to the source directory that is being built (the context of the build).

Each may contain wildcards and matching will be done using Go’s filepath.Match rules.

The is an absolute path, or a path relative to WORKDIR, into which the source will be copied inside the destination container.

https://docs.docker.com/engine/reference/builder/#copy

[dblandin]

What do you think of adding the bin/ directory to the COPY directive above to avoid this extra layer? It's rare that these bin files change so I think we can take the cache miss when they do.

[maxjacobson]

Hm I like that idea, but how do you write that? Trying

COPY composer.*|bin ./

But that ... does not seem to work 😅

[dblandin]

I would try:

COPY composer.* bin/ ./

[maxjacobson]

Hm. it seems to copy the contents of bin, into /, not bin itself. From reading the docs, I'm not sure if there's a way to get around that

[dblandin]

Hmmm, could you try without the trailing slash? I think there's a difference in behavior there:

COPY composer.* bin ./

[maxjacobson]

I think that behavior difference only applies to the <dest> parameter. I'm getting the same result both ways

[dblandin]

The behavior is a little confusing. Looks like when the <dest> has a trailing slash, the contents of the <src>s are copied in. If you want to copy an entire directory, you need to specify a specific destination: COPY bin ./bin

Unfortunately this means you can't mix and match so I think keeping the bin/build-content COPY line where you have it is fine 👌

[dblandin]

COPY bin/build-content /usr/src/app/bin/build-content

You can use a relative destination though:

COPY bin/build-content ./bin/build-content

[maxjacobson]

Niice. Updated

[dblandin]

The second argument here can also change to ./ since the WORKDIR is still /usr/src/app